The United States is militarily ready to carry out a strike on Iran to stop it from obtaining a nuclear weapon if international pressure fails, American ambassador to Israel Daniel Shapiro said to an Israeli audience this week. The Obama administration has repeatedly insisted that "all options are on the table" to deal with an Iranian nuclear threat, but Shapiro's comments went a step further in discussing the military's preparations for the possibility.

"It would be preferable to solve this diplomatically and through the use of pressure, than to use military force," Shapiro told representatives of Israel's Bar Association on Tuesday.

"But that doesn't mean that option isn't fully available. Not just available, it's ready. The necessary planning has been done to ensure that it's ready," he said.

The comments come just days before nuclear talks are due to take place in Baghdad between Iran and the so-called P 5+1 countries: the U.S., United Kingdom, France, Russia, China and Germany.

An embassy spokesman in Tel Aviv declined to elaborate on the comments, which aired on Israeli radio and television.

"We believe that there is some time, not an unlimited amount of time -- in practice, this is a brief window in which we can still use diplomacy to achieve our goals," Shapiro also said, according to Makor Rishon newspaper, which published some of Shapiro's remarks.

"At a certain stage we are going to have to decide whether diplomacy isn't going to work," he added. "We want to give it every chance of succeeding."

Shapiro pointed to President Barack Obama's increase of troop levels in Afghanistan and his order to kill Osama bin Laden in Pakistan last year as examples of Obama's readiness to use force.

Israel and the United States agree that Iran is working towards a nuclear bomb but hasn't yet entered the "breakout" phase of development. Israel's Defense Minister Ehud Barak often warns of a "zone of immunity" he believes is rapidly approaching, after which Iran could not be prevented from developing a nuclear weapon.

Prime Minister Benjamin Netanyahu said last month that Iran is "feverishly working to develop atomic weapons to achieve" the destruction of Israel. He and others in the country's civilian and military leadership have long warned that Israel would resort to a military strike against Iran if it becomes clear diplomatic pressure and sanctions aren't working. The result has been harsh international sanctions against Iran's financial and oil industries that are having a devastating impact on Iran's economy.

But despite some indications that Iran could make concessions in next week's talks, there is no evidence that the pressure has had an effect on its nuclear program. Israel says the international talks are evidence of Iran's stalling tactics and says that that unless Iran stop enriching altogether, ships in enriched uranium out of the country and shuts down its underground enrichment facility near the city of Qom, the diplomatic measures and sanctions have failed.

Iran has long insisted its nuclear program is for peaceful purposes -- that it enriches to 3.5 percent for power and to 20 percent for medical isotopes at the Tehran Research Reactor. But analysts say going from 20 percent to weapons-grade 90 percent enrichment is a relatively simple process.

Israel's leadership calls Iran an existential threat, but a large majority of Israelis are against a strike if it's carried out by Israel alone. Most analysts agree that an Israeli strike could not end Iran's nuclear program, only set it back. And some argue an attack would cement Iran's determination to develop a nuclear weapon which could start an arms race in the region.

The biggest critic of Israel's threats of a strike has been Meir Dagan, the former head of Israel's foreign security service, Mossad. He has argued that Iran is not an existential threat and that its leadership is rational.
In a Wall Street Journal op-ed on Thursday, he and other former international intelligence and military officials argued that more comprehensive "total sanctions" can get Iran to change course.

"It's common sense that before undertaking military action against a country, we should first try to dissuade it from its current course by applying decisive economic pressure," they write. "Doing so will show the regime that the world is serious and committed, willing to do whatever it takes to stop Iran's pursuit of nuclear weapons."